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comparison gcc/testsuite/g++.dg/cpp2a/cond-triv1.C @ 145:1830386684a0

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gcc-9.2.0
author anatofuz
date Thu, 13 Feb 2020 11:34:05 +0900
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131:84e7813d76e9 145:1830386684a0
1 // Testcase from P0848R0
2 // { dg-do compile { target concepts } }
3
4 #include <type_traits>
5
6 template <typename T>
7 class optional
8 {
9 struct empty {};
10 union {
11 empty _ = { };
12 T value;
13 };
14 bool engaged = false;
15
16 public:
17 constexpr optional() = default;
18
19 constexpr optional(optional const&)
20 requires std::is_trivially_copy_constructible_v<T>
21 = default;
22 constexpr optional(optional const& o)
23 : engaged (o.engaged)
24 {
25 if (engaged)
26 new (&value) T (o.value);
27 }
28
29 ~optional()
30 requires std::is_trivially_destructible_v<T>
31 = default;
32 ~optional()
33 {
34 if (engaged)
35 value.~T();
36 }
37
38 // ...
39 };
40
41 struct A { A(); A(const A&); ~A(); };
42
43 static_assert(std::is_trivially_copy_constructible_v<optional<int>>);
44 static_assert(!std::is_trivially_copy_constructible_v<optional<A>>);
45 static_assert(std::is_trivially_destructible_v<optional<int>>);
46 static_assert(!std::is_trivially_destructible_v<optional<A>>);